Volt gauge reading

[efnfast]

With the battery fully charged and car (2002 rt/10) on, intercooler pump on, radio on, headlights on (dtrl), radiator fan off, the needle on the volt gauge is just a hair past the 14 mark on the gauge.

Same conditions but now radiator fan on, the volt gauge sits a hair beneath the 14 mark if I'm driving (i.e., RPMs above 1,000), and maybe around 13 if it's idling around 750 RPM (with the headlights being pretty dim until the rpms kick back up).

Is that normal for a Gen 2 whose only additional non-OEM electric load is an intercooler pump? On other cars with a volt gauge usually the needle is well past 14 with everything running and my headlights arn't dimming at idle, so I've been wondering if maybe I should be replacing my alternator?

 

[Old School]

You’re probably right, that’s the classic symptom of diode failure in the alternator.

 

[Goggles Pizano]

Check the voltage. with an actual multimeter. Remember that the voltage regulator is in the PCM not the generator.

 

[MoparMap]

Anything over 13 is ultimately still "good" in the sense that it's providing more voltage than the battery is using. As others have said though, I would check at the alternator and battery terminals themselves to confirm the real numbers (with a good meter I might add, I learned that lesson a while back). The gauge will show whatever the PCM tells it to, not necessarily the "real" number.